This paper focuses on school improvement processes in the context of weekly curricular-based teaching and learning activities outside the classroom -- known as "Draußenschule" or 'outdoor school' -- in three German primary schools. Qualitative interviews were conducted with three teachers two years after implementing the 'outdoor school'. The teachers' experiences show that the implementation and (ongoing) development of an outdoor school affects (1) teaching as such; (2) the school staff, and (3) the entire school as an organisation. The three areas are interlinked in different ways and the school improvement process cannot be approached from the perspective of any one area alone.